Remain in same page even after submitting the form

I'm using a jsp to post data to a servlet, but after posting the data i want to stay back insame jsp.
Briefly:
1) I have a jsp here with 2 textboxes. i use a javascript to copy data from one to another on a button click.
2) I use the same button to post data to a database.
3) I want both the actions to be done at a time and should not go to the third jsp(servlet post result), but , should go to another jsp i use.

i'm able to handle these 2 things seperately but together i'm unable to do it. the data gets updated in database and shows a new line in the first text(that's my fault i'm using the redirect way) or moves the data from first textbox to another and doesn't do the data posting. please help me about doing it. below is the code piece i used to do it.

I want to both copy data and post it and stay in the same page with the value copied to the second textbox, i don't want a redirect or a refresh done. it should be like the posting to be done as a masked process i.e. user shouldn't know that there is a post operation going on in the backend. And Bear, i'm not aware of this Ajax i learnt Servlets after you suggested the previous time(and i sincerely want to thank you for that), if i should use ajax could you please provide me a sample code that goes here and also suggest me a good tutorial site for it.